SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '618d26bae5387109eb825607444f7de0cf955894441055c73fd886acd6eff203' 
  AND token = 'B319XU2EQMZqGdeyx3OTcFXBoR2bwlH8WiiCSSUfJGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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