SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a66ea4ed19f10902c50737b9a5713381e3f62fd93eb4a74355259bda3f72079' 
  AND token = 'xFG5bjoebl3oiqJKR2OYomIJDgpMlbPrTTjS15t5LdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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