SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a1ffbf9e23d050cc378f1af302b1fc098b97ab3af839d69f7d492e8e901b173' 
  AND token = 'blz6fr2RVPskE33nGjRXHymxbF+RVlc3Vxc2MyIcfTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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