SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8266122bcda8aa3dfe011d763016ac26ce4f722fb0faf7c81ad7902735839cf5' 
  AND token = 'i9EQpGHf1Y+9fUDdOjNPyxLisVgxvMHtPBMu8z74vUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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