SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae6917d7c7b7d1aa99d11468943f77b1d6a10b7eb2b7ad367bbc12adbe322068' 
  AND token = 'mAbOo64dbeRyXmQJtsLfNDGbNU2WVvafF1OsgDlvoZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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