SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '772c27ad43a93ef9988887c679198da6f958e4d14289820db9c6db91efa5095c' 
  AND token = 'Offt9Gd23TymbGejtUztaP8mvhPnRHfO9TMFeBvV4T8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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