SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb781e90074163bc22bbda6e19d010836fdb706b30f7606d1736edf067a4eb2c' 
  AND token = 'zYRU69yE0t/kxjWsje/bXkd5VDGDloiT8YJhh89gnuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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