SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a49f6592d8d4d67d35ef20137264c1e8b5a5f6d552492fe4bfe8204464e42279' 
  AND token = 'AQtocXB0Tdr+zPckG33bKQzhcGi/ZHhZ3WMovFSVlmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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