SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '412ccbee98405925df9ece4aa00e8ec6e655665417bf48f13560906f2127bdf6' 
  AND token = 't4WMvkjYqxCt9KCfhp9ZL8zQ7VlXIyOP586IoqsFGzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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