SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2ab624e65ac05ca979253a26a97a20aee39d42f696de11ccb02082eacc92e9b' 
  AND token = 'AxAC7ZuebSFdf6aH8HLQnMLVXACNeOnJ8H73YU0u1rY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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