SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2447c57cd1f179d21adca2180e1d93916f14ad2248714778f5c6d984ccf8b284' 
  AND token = 'xOHqqCKVd6MZUPvgd4vosLXhbuzkoDMAyMpJqkysqVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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