SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cec6c759360f257ea0f2bbcd96cc74fdc4b2b2c11110817f45929f8a6e885785' 
  AND token = 'UwiGunirIjRukxvfhbqoS3KISA3zZ6oOv1JT6exbBqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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