SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fcc97bc84931d849685b912c2b71ee182522255a04e887b3f36820a959c7674' 
  AND token = 'lXTuMYRhZnzpt3VGkqenf7KTuxkBboIWNjU2zTHCfWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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