SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f697ea266bed28a9a54426abc33092e99a066bcd302050c8a07314cf96ebafe' 
  AND token = 'Ri9LeaAnEmGBULWMTGr0p7uOugd0QApKjSyhmOTSRzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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