SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '207f0fbc093075c732c0c27007d89b0fb8df651b9850ccae34e03fc93733555a' 
  AND token = 'GKGPYS1Sqxo9BdZN7GbTZ1p/4hJhWj+USgmCVcQH0rI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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