SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80cf3f828c68d1e457991338fb14a40fe37eba45e198520c0d4d5a46fdfa3454' 
  AND token = 'kQmQLzpF6DdanywyWF8tyFIZna4is6gsMaaSbYXZMp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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