SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c713590a502e256c552d2341665ba106aab51254b760fee0f01c4ff389b8dbd' 
  AND token = 'TTlH3DJB8xBd5dEUbM2TAK4hHXOTLCjHdKm++3fsRBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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