SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9104cfa3998a21eaa1d6ba4cadeb3efdadfab28197a3b6057b7519aceec5437b' 
  AND token = 'CJ8ST2jwuoevy/G6IlykgYeqqQnVu2ofc+omxBl2Rr0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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