SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb90e20395a3361bd1e630a91f75ada10a24cde3feb61a7ba673549a8f8db84d' 
  AND token = 'UslOFFSmPRVfDFOPNxWlQLCrxWIMem8gnTy7q9ONX+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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