SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'badfe18bbba62f1b127f83cac006a351f495823738995a9e588cef162bebd541' 
  AND token = 'sxQD1Ol8x4/BKf5SlJT7zHjOyTuoNgr18T4IBWfCCqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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