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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a18e3e2a39e4cd56fe872d4f80de44a28f417f8a06cc73ad8d4367e3e4a5d90b' 
  AND token = 'rE4KzGSgNacPaVpEgaDb7SVH1xc+BWoygI5YECGDqcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}