SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcf31580b9688a02f2d054656d295aae60372f391a056e10597069094765530d' 
  AND token = 'sFSezkSklUV7z5bkXvUaXV/YbmznrffJ2wcab0dB+eE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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