SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cce76906161c0d871cf3f7d94e44ebd25a481a748d1ca3cc5c97eee3a02d4c27' 
  AND token = 'TXY5yr9ZQDdVrTnGufnmPi8BvqfR0hHeHmNhlHFUinE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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