SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe326a98412eca72d9e6030440b18adcc31b0ce59c6607be71a53c6050007cb8' 
  AND token = '6RzhpLfPOQBHTIHC51aKREZltw7Z0JGksonBiUGYdN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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