SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f61fe05ec52fd2a7586197821cfd71663b3ffd0c86bf747c3e3c6da598f84e9c' 
  AND token = 'XQYzy/QDR68NLLlP23h/blOcG3ETQkNMT4oACOXnfAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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