SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d3191abf31ec1f19e2cdd99e2c077f46ba317c95f6d44a25c7b9bfd4f080d27' 
  AND token = 'Z8P1TFwPVzM9CR4hf/VcgXeiUbmUZE+cvKU9j9tYNCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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