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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4966f39ea4d06357d203dcbf426f8fd87fdb674199eff83b0f669e733f9ee36c' 
  AND token = 'EFmq7iqQvH8hitfUl+V8T6IjawISSnpgEmzKxaMrMyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}