SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '464d94a68d7dc7de158a17ae17c7fc389609a3297a4c249185d90b723b64aa52' 
  AND token = 'vhhk/JDMDgiUWlKJs3fy9vGLh4LNSSfcjubZRIYFe5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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