SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cee193f0a5a76945718f289989fc94b38955f1e2f8915eed13523b134802e605' 
  AND token = 'L5zorBRFRycz2QTgfayTvp2IhvRQqOo+nL7m/ONm+JI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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