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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7ead8263a3c72a532faf1c4b70357e75539f981ba60205af4ea8fd7865a4a87' 
  AND token = 'ekTVqr/7FXY522T6/UJt0XmQollegx8X3RNpIBDR0rI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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