SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4158d800ac74e50f57dabc8d6b8695bf9ab4631dd3a3174df96b4d6508272f12' 
  AND token = 'HZ5Hz1M9CXXrxZS1PVBgxjBKf5Ti+3fXO8ksQr7gAV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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