SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04321ffcc8f2909d895f75319ed48f12281b90164d2dbc26ca6defb538cbbed9' 
  AND token = 'LO0KugE8kyvee9nEbbgs+Gtw+2j2zPLy4AyAygD8se4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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