SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '773e9ccdc6463241e79e60b5f12fe79a8e3bf9423079489e87c42a87a86c4bb8' 
  AND token = 'LqazFiJwx+TA1GvtCWPi0kxugUgtpWiyGnlRKWegqj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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