SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fa5399c72251e4684366aeb925d866d8ea5c5269cac8a941ba78ec30ae89d83' 
  AND token = 'fxHWCkNVvzBcPmY8tIBEXmCXZ/+eGJ6lsPrhU5YLzW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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