SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '797c3ec00f88c400b5762f4b7896ae611420a150c571dc0321b088e748a3ebb0' 
  AND token = 'W9nGrCVkr8DF4NUNdg3chQUhfeuK8J7RgVDjZBe+drQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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