SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59171ae93729955ae45ca18a87da495f005251ffe3a8a31266eaea55641b96b0' 
  AND token = 'byDLxU2QS92segz4Et73hqyaepcCaNSY4xmhma0cylU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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