SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'df586d87f28b8fd33d17076f347908f94b3fefab43bdce831a383a1758280747' 
  AND token = 'BjReIgOPvVBU2CXRz10Aj4txEjQRuxCCvfSSB+tmHQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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