SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbbfd1ab14115377d6b8e879660775593f20dfc5dbb3791cd382bd8158a3985a' 
  AND token = '5+HIwSlILFXscgaoAEmAab0aSGawz4dlUqYbeyqXK1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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