SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9503b43d9228b6a600f18003247c4da78eeab1f50e7c06721c26c4eba87561dc' 
  AND token = 'uVWQTNtxOUydbXB/jOs57zJ+1Bbg6ovVcoxbmQnMgZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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