SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '891c3977378ef7c634e39962403e3485ccf3a42c53ea8224406d3f1004f58b49' 
  AND token = 'p3QSW0ZgEPPKd6rHAazwX9QQ5clN3Lv3TsI5GFms8Vs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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