SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab50d8eff39b408d6f158376e78db7b353ae24c76af2b8b8b13ccff3b21542d8' 
  AND token = '82iu5s19gz2Er3C/yF+wH2sY09G5mAVAxKS+hpiAhjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}