SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f1b35780baa09f0db1532990167b3f75ba8ca8b52c4105a54dee76d9d47b6c3' 
  AND token = 'WlvQAPjY0lRtKJ/NAXkVADD4umG7RvugF3ECIeoD7fY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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