SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31ba7c0640f00509eb4408044221dd9a10c269333e1bfe549e42007a5550b661' 
  AND token = 'qAJyKRcdbTVME0jPGbloUFD34CechKjGVRchSQTzokw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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