SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b46d49917fa1a8ecd1e12a5bbe76f75755574786fb305020c626daa8b325b3f' 
  AND token = 'yRxZSwlcyyyZegqcuDa/9yyg3FJ0p2OWz8Mp1/LXTS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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