SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a377c6f7bc910fa2336de9902fd2a3e10b1d235189b25d466a55389b8d94417f' 
  AND token = 'Vk7mk45CHa+UJQZKBbzasFonPR/a+XCVdxFMXDRRXLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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