SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa263b755229fa01173cf56bd1ea8c3b200fa2312336f4730bd01fedb900e1d5' 
  AND token = 'm0kK/o+60xF5a/+57eNI6C8pXQ6TG5T4PZ4ff3K6Ivk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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