SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66612927090b441d7782ac17783c1441af1371bd37266e890799036eeb64bba5' 
  AND token = 'cpjsu3HBf+UAmPpoh6mM9JGo2MN0yz9wo4DBfTaxeqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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