SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9cf273bac00c307614c60ada540490d09823565b790dfaa41d50d3d4bb10f7b' 
  AND token = 'F/9ss8yv7YSMPtIxYwfvq+l9mK1cdEQEjscao8SYRQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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