SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89c14df8f7f47c5e45780925983a716a304fe0f41055ea5a737789d7669fec18' 
  AND token = 'SlG5xnDOd8olRcvNmkjdwdRJBLO6dvu/XsMckAbgg58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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