SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a467be11ad8e8b234ae175c7404514276d25f89e050c795ad1ec629af5c96d14' 
  AND token = 'PBStjPMH1uf4vWawHnhSm096p7jUb0D/685CUJrzdqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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