SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcde5a9bed8b50901e62b8642b34664542d0a84fef353b48971c6e3eb0e33080' 
  AND token = 'gKeUUmKkNCjXXXMLvUTvvJrr17/G5fc6jGNm2q1AODU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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