SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a66654d925f40dfdfebca1a8ff17df79d07dd105e64c220362439b57f333337f' 
  AND token = 'fGUUHaLEpIm+sppK+qFZNcdEA602/CfOdwLvEMMdZWk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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