SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f3e97acbba3d7c7a07bd4dfdb36795e2afd840b4eea04a51a600471305c85f5' 
  AND token = '0hcVSzwELC5bSM6DWwoT8usyX/vXAuP+WtgawDU8Qoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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