SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35b46d816c9953679c47adc351c1f4309f9405ae42fb127e20ded5c863ac97d0' 
  AND token = 'DSyRhSb7Ucr++hC2uEIkZUzvM/BOBgBs8eqIYI1nAjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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