SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56c2bfd62833f3fec43f4936b1288f2d7fc827dedde2840c8d7147d619029030' 
  AND token = 'G86xH3eObsqQhyQGGwqxpPlBsyckSAnzmwME7DcEeI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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