SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cde12f2c258d201b0c4d50c038ec00c5bc07473d5b69585814a2a19afa1581b' 
  AND token = 'xqX+6RrruGXcBReEldUufCTK63YtKWLFL/KLoGi9YxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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