SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfe401f0e8b0f11d7add715e65791fba0b19bde22053d91f65c874ef1af16f7a' 
  AND token = '1aVr1u42wtmPSnxXYacunZRkS45wGP4ApcdzcDe2Iig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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