SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2daf96503370498ef43f1a888e75fd684b3d5b88cd5875ab5af6032722807a50' 
  AND token = 'hktU/rpCdMgb6CScbWsD7oCXO6hDqP03YTecKkR2CE0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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