SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a52235bfef3bc0b8a496fca77d050d08dc3b857e17d28389516a0129661a349a' 
  AND token = 'qNY3GAlQgUsSCot6Umq0ywZkb4ccJVnkx7bWf87XEPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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