SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79ddc55db499206993151e98aefa61f82be102d5703b68dbdc9df4f8edef9d22' 
  AND token = 'Yhr3KVRl+1p0vqCcHsSj7cJKm++uUHIMCiqEzsnVtRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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