SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a76701d42908f726e1f8f79d3136238a056b97c198c46d929a6833a7b62e42b2' 
  AND token = 'HY365UpwgwXyWu/qV1+RDx9zSS5WZ1EVsU/bRYgW+8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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