SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33c9ea204db5dd3766250d59ae0c81441f09e185fd0e60e332bfbc2b2ff8bca8' 
  AND token = 'Ul1rFM0OIYec75eCiUYs95OrWCqfub72K5F/eiFU2Uw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}