SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '778ea5c6db9a7fd3bd07a6f3ec9364a00b06a35c988962d0c042a5c194e14c9c' 
  AND token = 'Yj1t6vHKjVuXW4xdDruXzKTn+sQhdO35nWox/gmVhKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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