SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f6c40a82ba7895951e2808f97950ea99d291ed4ce1bc31e98871c7c329f44c1' 
  AND token = '4ewv0JQo4TS4FNhvIg2s6JgLNqQV0gdpPdsXhywZbdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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