SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '598e1e9d368d79515b839c81225a1b97be89f97c3b208d9285019c34ebb4c530' 
  AND token = 'z+hi1sgNLyO5ZRZYGlYiBO7DTVSdpS81k5TxY3JMxAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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