SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a736fcfb99098fe7ec0e83f4913dd617f6cc2356d1a60983fb2a4830d2106c7' 
  AND token = 'cdvvtWylTLccBPFn4//XopilfWO1ixJyH1AO5FdxsJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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