SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c87ac76186b4bc0113f2eb8a82cd27b06eaa4927e8ffe46825c85b9245510330' 
  AND token = 'bU4zvR+z8xN7mIs6cxZPKvyBcdWGq8V3wVGutCbAmqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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