SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f36250eab0be66d3baa5b49c21bb4e6c247f3ef2c871da80087a757e2f92d17' 
  AND token = 'RH5NbcTH32C25lRXGc5Wq3jHl0iNaLgBFGEAEOzAJ+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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