SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c0e81e870e9fe365ad156718ddc80f2b678afab73850d484e8f1d3d582cc21e' 
  AND token = 'O4HlvotwTKPiN7aVnKncdcUOpzzDcJEWSzlktQbcjwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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