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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c03e954c714a5763fcfbd063a583967db93bcc09f02b8cacaa6ecf38d7bc4b98' 
  AND token = '1CWe725jE8+6cH3gLX1grLQMQEYuwhWPIBy1o3xqmlw=' 
  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"
    }
  }
}