SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a31e680e90a320b3895cdd041d2976819b42987f9b53c856c9a4020de6cc67e7' 
  AND token = 'G6Gt+LmKWUo85mqpJuHkMxct89y11sEnyDnNOkKDy/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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